There are two ways to access the EJBs: 1. JNDI 2. DI
Advantages:
- Removes JNDI lookups
- DI can inject this:
- @EJB
- @Resource, @PersistenceContext, @EntityManager
DI is supported within:
- Enterprise Java Beans
- Servlets/JSPs/Filters/Managed Beans/
- Applicaiton Client Container clients
Annotations:
@EJB
Example of dependency injection EJB -> Servlet
[code language=”java”]
// this is servlet
@WebServlet(name="DICalculator", urlPatterns = {"/DICalculator"})
public class DICalculatorServerlet extends HttpServlet {
// Line below injects RemoteCalculator bean into this servlet
@EJB
private RemoteCalculator calculator;
// now we can use the injected object
int sum = calculator.multiply(5,5);
RequestDispatcher dispatcher = request.getRequestDispatcher("calc-result.jsp");
[/code]
@Resource